Electric-circuit controller.



H. W. LEONARD.

ELECTRIC CIRCUIT CONTROLLER,

APPLICATION FILED APR. 6, 1906.

Patented M3122,- 1909.

I/ENTOR MM Brv ATTORNEY WITNESSES:

NORRIS PETERS, |NC.. LITHO. WASHINGTON. D C

PATENT OFFICE.

Y HARRY WARD LEONARD, OF BRONXVILLE, NEW YORK.

ELECTRIC-GIRCUIT CONTROLLER.

Specification of Letters Patent.

Patented. March a, 1909.

Original application filed November 30, 1901, Serial No. 237,653. Divided and this application filed April 6, 1906,

Serial No. 310,201. I

To all whom it may concern:

at Bronxvil'le, in the county of'VVestchester' and State of New York, have invented certain new and useful Improvements in Electric-Circuit Controllers, of which "the following is a full, clear, and exact specification.

This application is a division-*of my pendmg application filed November 30, 1901, Serial No. 84,188,renewed December 20, 1904, Serial No. 237,653, granted April 10, 1906, Patent No; 817,719, and relates gener ally to controlling switches and has a articular application to motor starting r1eo-- stats, or rheostats employed with electric motors or other electrical translating devices, in which the resistance is employed not for regulating the energy supplied to the motor or other translating device, but mainly for gradually raising the energy at the terminals of the translating device to the full electromotive force. My invention is also of importance where regulating resistances are used and to prevent their improper operation. I have found in practice" that such rheostats are frequently damaged by holding or permitting the contact lever to remain on the initial or starting contact or contacts near the same with all the resistance of the rheostat or a considerable portion thereof in circuit. I have also found that'operators frequently close the circuit at the initial or starting contact of the rheostat and then return the lever to the idle position, thus drawing an are at the initial contact. This also damages the rheostat. I have also found that operators sometimes close the main circuit when the resistance controlling device, which might be used as a regulator, is in an intermediate position. This, of course, allows an excessive and damagingflow of current.

The main object of my invention is to devise a starting rheostat or controller, or to provide the present type of starting rheostats with a controlling device, which will prevent this improper handling of such rheostats. Y

The full torque current is the current which the motor-takes when developing its full rated horse power. In starting any motor, it becomes'necessary to iplroduce a torque larger than that due to the 11 torque In other words, this starting acceleratin current is fifty per cent. larger than the ful torque current, that is, it is one hundred and fifty per cent. of the full torque current.

In order to prevent the burning at the initial contact, of the rheostat, due to the closing of the circuit u on insufficient surface, or due to the bee ward lnovement of the contact level after making the first contact, which results in the formation of an arc dueto the full electromotive force and one hundred and fifty per cent. of the full torque current (when the motor has no counter electromotive force), the rheostat should be provided with an auxiliary switch, by which the circuit is quickly closed upon an ample surface, and which switch willopen the circuit with a snap-action when the contact lever is returned to the initial position. This auxiliary switch should be beyond direct hand control in opening, and may be mechanically or electrically controlled by the rheostat contact lever or controlling switch.

In my original application, I have disclosed two forms of my invention in which the auxiliary switch is mechanically controlled. The resent application relates more particula to forms in which the control of the auxiliary switch is by electrical circuit to the rheostat and motor.

drop suitable manner beneath the base or within a casin and the sections of resistance will be insu ated from each other, and in some instances provided with means for absorbing the local energy developed therein.

B is a switch in the form of a rheostat contact lever pivoted on the base. The su ply conductors are indicated at P and N, and the translating device controlled is shown as a motor M. The auxiliary switch C is shown in the form of a brush switch. A controlling coil for the switch is shown at 0 which coil is connected between conductor P and a contact 0 with which the insulated short arm b of lever B makes contact when in contact with any of the rheostat contacts a from the second to the final contacts, but not when in contact with the initial contact. Switch C is provided with a rod 2 which breaks the are on carbon contacts 2. This switch is mounted on a vertically sliding rod 2 provided at its 11 per end with a stirrup 2 within which wor s a foot 0 secured to the lower end of rod 0 projecting from the core or plunger of coil 0 The vertically sliding rods 2 and 0 work in suitable guides and the lower end of rod 2 is rectangular and works in a correspondingly sha ed bearing to hold switch 0 in alinement wit its stationary contacts.

' .The rheostat lever B is shown in its second position, and the circuit to coil O is closed and its core is drawn up and switch C is closed. If now the operator returns lever B to the initial position, coil 0 will become demagnetized and its plunger will drop striking a blow to the stirrup, the force of which and the tension of the brush switch, will drive the switch downward. and open the When the lever B is moved forward, closing the circuit again at contact 0 the plunger of coil 0 will rise, and through the engagement of foot 0 and stirrup 2 switch (3 will be closed. It will be understood that upon failure of the line voltage or upon the occurrence of abnormally low voltage, the current in coil 0 will cease to flow or become so Weak as to be unable to sustain the weight of its core or plunger which would thereupon and automatically effect the opening of switch C. This coil and the switch therefore serves as a means for protecting the circuit from no-voltage conditions.

It will be noted that I have indicater motor M in the drawing having a shunt field winding, and that the supply circuit to both the armature and shunt winding is o ened by means of the automatic switch 'in t e main circuit.

for the field discharge.

It is evident that mymvention may be embodied in various forms of construction,

Also, that when the" circuit is opened, the armature and field-a s closed on themselves giving a closed UlICf lt and that I am not limited in the scope thereof except as indicated in the following claims.

Having thus described my invention, I declare that what I claim as new and desire to secure by Letters Patent, is,

1. The combination of a motor rheostat, a circuit breaker, a coil for holding said circuit breaker closed, and circuit connections controlled by the movement of the resistance varying element of said rheostat for controlling. the opening of said circuit breaker by controlling the current in said coil.

2. The combination of a motor rheostat, a circuit breaker, a coil for holding said circuit breaker closed, and circuit connections controlled by the movement of the resistancevarying element of said rheostat for controlling the closing and opening of said circuit breaker by controlling the current in said coil.

3. The combination of a motor rheostat, a circuit breaker, a coil for holding said circuit breaker closed, and a contact engaged by the resistance varying element of said rheostat at or near its initial position for controlling the opening of said circuit breaker by controlling the current in said coil.

4. The combination of a motor rheostat, a circuit breaker, a coil for holding said circuit breaker closed, and a contact engaged by the resistance varying element of said rheostat at or near its initial position for controlling the closing and opening of said circuit breaker by controlling the current in said coil.

5. The combination of an electric motorhaving a shunt field winding, a starting resistance, the motor armature, field winding, and starting resistance being connected in a permanently closed local loop, a movable element for varying said resistance but not adapted to open the circuit, a switch in series with the motor, a no-voltage coil for holding said switch closed, and a contact device for controlling the current in said coil and controlled by the movement of said element.

6. The combination of a supply circuit, an eectric motor, an armature rheostat for said motor having no open circuit position, an automatic switch for closing and opening the armature circuit of said motor across said suppfy circuit, said automatic switch having a tendency to move to its open position by gravity, an electromagnetic coil for normally holding said switch closed against gravity,- and means for normally controlling the clos. ing of said switch when a protective amount of resistance is in series with the motor armature and the opening of said switch after closing said switch when energized and which upon no-voltage allows the switch to be moved by gravity to open position, acontact device for controlhng the magnetization and demagnetization of said coil, and means for controlling said device by the movable element of said rheostat.

8. The combination of a controlling rheostat, a switch in series with said rheostat, a coil for automatically closing said switch and for holding said switch closed, and a contact device controlled by the movement of the movable element of said rheostat for making and breaking the circuit of said coil only when the resistance of said rheostat'is in circuit.

9. The combination of a motor, a handoperated rheostat in series with the motor armature, a switch in series with said rheostat and armature,- a coil for closing said switch automatically. and for holding said switch closed, and means for closing and opening the circuit of said coil for closing and releasing said switch, said means being controlled by the movement of the movable element of said rheostat when said element is at or near its initial position.

10. The combination of a controlling rheostat, a switch in series with said rheostat, a coil for automatically closing said switch and for holding said switch closed, and a contact device controlled by the manual move ment of the movable element of said rheostat for making and breaking the circuit of said coil only when the resistance-controh ling movable element is at or near its initial position.

11. The combination of a controlling rheostat, a switch in series with said rheostat, electro-magnetic means for controlling the automatic closure of said switch and for holding said switch closed, and a contact device controlled by the movable element of said rheostat for making and breaking a controlling current for said means when the resistance-controlling movable element is at or near its initial position.

12. The combination of a motor rheostat, a circuit breaker in series therewith, electrical means controlled by the movement of the movable element of'said rheostat for effecting the closure of said circuit breaker against the action of gravity, said switch being automatically moved by gravity to a protective position upon the occurrence of no voltage.

13. The combination of resistance-varying means, an automatic switch, said switch being acted upon by gravity for securing the automatic opening and having electrical means for controlling the automatic closure of saidswitch, and electrical means for progtectively relating said resistance varying means and said switch.

14. The combination of an electric motor, a resistance having a movable element for varyin gsaid resistance, an automaticswitch :-c'om rising a laminated mam contact and an auxi iary hnal break contact, said element,

switch and motor armature being connected, in series with each other, andmeans controlled by the movementof said element for trolling the automatic movement of said switch. j

15. The combinationof a supply circuit of constant electromotive force, an electric motor, an armature rheostat, the said rheostat and motor armature and field winding of the motor being connected in'a closed local circuit, a switch forconnecting saidilocal' cir cult to the supply circuit, and means comprising a coil for automatically closing and opening said switch, the magnetization and demagnetization of said coil being controlled by the to-and-fro'movement of the movable element of said rheostat and thereby causing the closing and opening of said switch.

16. The combination of a motor-controlling rheostat having a movable element for varying the resistance in the circuit, a contact made and broken by the movement of said element, a coil "energized and denergized res ectively in response to the making and breakin of said contact, and means con-. trolled by said coil for controlling the current through said rheostat.

17. The combination of a circuit-controlling rheostat having a movable resistance varying element, means for causing an auxiliary electrical contact to be made by the movement of said element to a certain position and to be broken by its movement in a direction to insert resistance, an electro-re-' sponsive Winding, the current in which is affected by the making and breaking of said contact, and a switch responsive to no voltage controlled by said winding.

18. The combination of a rheostat having a movable element for varying the resistance, a switch in series therewith, magnetic restraining means for holding said switch in closed position, and electrical means for releasing said restraining means to automatically control the opening of said switch by the movement of said element when sub-. stantially all of the resistance is in circuit.

19. The combination of constant electromotive force supply means, an electric motor having a field winding energized independentl of the working armature current, a control ing resistance for the motor, connections forming a permanently closed local loop in eluding the motor armature, said resistancr and field winding, a protective switch, said local loop and said switch being connected in series with each other across said mains, an electro-responsive winding for automatically causing the closing of said switch, said winding being connected in a branch circuit across said mains in parallel with said loop.

20. The combination of an electric motor, a resistance-controlling movable element in series with the armature ol' the motor, a functionally related automatic switch in series with said armature and said element, and means for automatically closing and 0 ening said switch upon movement of said e ement by the operator, said switch being automatically responsive to no voltage in its opening movement.

21. The combination of 'a motor, a switch in series with the motor armature, a motor controller having a resistance varying movable device and functionally related manually controlled auxiliary contact means controlled by the movement of said device, an electro-magnetic coil for controlling the automatic closure of said switch, said coil bemg responsive to no voltage to control the automatic opening of said switch upon 00- 20 currence of no voltage, and said contact means and said coil being functionally related to cause the automatic closing movement of said switch when said resistance varying device is in a certain position and also to con- 25 H. WARD LEONARD.

Witnesses L. K. SAGER, GEO. A. HOFFMAN. 

